The present invention is directed to the field of retaining rings for removably joining two flow members. The invention has particular applicability as a retaining ring used with a spray gun system for securing a sprayer aircap to a sprayer.
Previous sprayer systems have used an indexing aircap that can change the spray between a circular pattern and a flat or "fan" pattern. This is accomplished by having different air passages within the aircap. A central air passage is included in the aircap that creates a conical airstream which atomizes the fluid from the nozzle, producing a circular atomized spray pattern. A fan pattern is created by a pair of air jets, which are formed in the aircap to point generally toward the directional axis of the central air stream. When air is injected through the airjets, the circular spray is "flattened out" so as to produce a fan pattern.
Most common aircap assembly designs have a "dial" configuration, where the aircap can be manually turned between a circular pattern position, where the air jets are blocked, and a fan pattern position, where the air jets are open. With this aircap configuration, it is necessary to secure the aircap in either respective position before spraying. In one previous design, the aircap is indexed by loosening the retaining ring, turning the cap to the desired position, and tightening the ring. This can be an awkward procedure for the end user, who must perform these steps while holding the spray gun.
In another previous design, as shown in FIG. 1, a coil spring 12 is added to the inside of the retaining ring 10 to bias the aircap 14 into sealing engagement with the spray gun assembly 16. In this way, the aircap 14 can be turned to the desired position without loosening the retaining ring 10, permitting easier operation. However, the coil spring 12 is difficult to install and easy to lose, resulting in inconvenience for the end user. Also, including the spring 12 as an extra element adds additional expense to the cost of manufacture.